Alternative refrigerants such as HFC-125(C2HF5) and HFC-32(CH2F2) have been widely used as important replacements for CFC, HCFC, etc., which cause ozone layer depletion. However, these alternative refrigerants are potent global warming substances, thus creating concern that diffusion of the refrigerants would increase global warming. As a preventive measure, these refrigerants are recovered after use. However, complete recovery of the refrigerants is impossible. In addition, diffusion of these refrigerants due to, for example, leakage cannot be ignored. The use of CO2 or hydrocarbon-based substances as alternative refrigerants has also been investigated. However, because CO2 refrigerants have low efficiency and devices using such refrigerants inevitably become large, CO2 refrigerants have many problems in terms of the overall reduction of greenhouse gas emissions, including energy to be consumed. Furthermore, hydrocarbon-based substances pose safety problems due to their high flammability.
HFO-1234yf (CF3CF═CH2), which is an olefinic HFC with low global warming potential, has recently been attracting attention as a material to solve the above problems. HFO-1234yf, used alone or in combination with other substances, such as hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), and hydrochlorofluoroolefins (HCFOs), is expected to be useful as a refrigerant, and additionally as a blowing agent, propellant, extinguishing agent, or the like.
Various methods are known for producing HFO-1234yf. For example, there have been proposed methods such as a method in which CCl3CF2CH3 as a starting material is reacted with hydrogen fluoride (HF) that has an amount exceeding the stoichiometric amount (Patent Literature 1), and a method in which a fluorocarbon represented by CF3CFHCFH2 is subjected to dehydrofluorination treatment (Patent Literature 2).